One such manipulator serves to exactly position a test head relative to the device handler with which, for example, electronic devices, for instance ICs or wafers are furnished so that proper functioning of the devices can be tested by the test head. To obtain a true result, the relatively heavy test head needs to be advanced as near as possible to the device handler to ensure precise docking. This requires precise and smooth positioning of the manipulator positioning the test head three dimensionally. In addition, a compact design of the manipulator is called for since handlers for IC or wafer devices generally find application in a clean or ultraclean room environment requiring an economic footprint.
A manipulator of the aforementioned kind is described in German Patent DE 40 07 011 A1. This known manipulator comprises a vertical guide column on which a positioning means is arranged height-adjustable. The positioning means comprises an extension arm for pivoting in the horizontal plane and mounting a pair of dual articulated arms. At their end facing away from the extension arm the dual articulated arms are connected to a holder serving to secure a test head.
A generic manipulator is furthermore disclosed by the German Patent DE 35 24 348 A1.On this manipulator a pair of dual articulated arms is connected at one end to a test head and~at the other end to a height-adjusting lead screw. The dual articulated arms can be locked in position by clamping screws.
Although the dual articulated arm configuration on the known manipulators permits both linear displacement and pivoting of the test head in the horizontal plane, there is the disadvantage that the motion of the dual articulated arms cannot be repeated with the necessary accuracy when translational motion is combined with rotational motion. The fact that the manipulator known from German Patent DE 40 07 011 A1 comprises an extension arm permitting rotational motion in the horizontal plane also fails to change this situation. For, the rotational motion alone fails to make it possible to displace the test head sideways, for example.